ATHENS, March 31 (Reuters) - Spain’s Repsol has entered a so-called farm-in agreement with Energean Oil & Gas for a 60 percent stake in two onshore blocks in western Greece, Energean Oil said on Friday.

Under a farm-in agreement, an oil and gas company acquires an interest in a lease owned by another group.

Repsol will become the operator of the Ioannina and Aitoloakarnania blocks and plans to acquire seismic surveys over the areas in the 2017-2019 period, Energean said.

Energean, Greece’s sole oil producer, holds an exploration licence in Ioannina and is expected to acquire one for the other block.

Energean did not disclose the size of the deal, which is subject to Greek approval.

Energean Chief Executive Officer Mathios Rigas said that the agreement was a significant step forward for the development of the Greek oil and gas sector.

“Repsol’s expertise and Energean’s knowledge of the area’s geology will undoubtedly drive forward the possibility of making new discoveries in Western Greece,” he added.

A consortium led by France’s Total signed earlier this month a deal for deep see gas exploration in one offshore block in western Greece. (Reporting by Angeliki Koutantou; editing by Alexander Smith)